Leptin is a hormone produced by adipose cells and utilized by the body to regulate fat metabolism and appetite. Major depressive disorder(MDD) is associated with significant mortality and morbidity, w depression-related anorexia and weight loss contributing significantly to poor outcomes in elderly patients. Glucocorticoids (GCs) such as the endogenous human GC, cortisol, are the product of a stress-responsive hypothalamic-pituitary- adrenal(HPA) axis, and numerous reports have indicated increased activity of the HPA axis with increased cortisol secretion in patients with MDD. Recent studies from this group have indicated that GCs, including cortisol in humans can robustly increase circulationg plasma leptin levels. This suggests the hypothesis that HPA axis activation in MDD, through cortisol-induced stimulation of leptin secretion, may be related to the anorexia and weight loss often associated w this disorder. This pilot study aims to test for an association among plasma leptin concentration, plasma cortisol concentration and body mass index (BMI) in older and younger MDD patinets with weight loss in comparison to MDD patients without weight loss and healthy control subjects.